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Hydration and Conformation of 2-Ethylfuran Explored by Microwave Spectroscopy
Charlotte N Cummings1, Nicholas R Walker1
1Chemistry- School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle-upon-Tyne NE1 7RU, U.K.
The Journal of Physical Chemistry. A
|May 14, 2025
Summary
Chirped-pulse Fourier transform microwave spectroscopy revealed structural details of a 2-ethylfuran···water complex. Hydration by water reverses the preferred energy order of 2-ethylfuran conformers, indicating a weak interaction with the ethyl group.
Area of Science:
- Molecular spectroscopy
- Physical chemistry
- Supramolecular chemistry
Background:
- Understanding non-covalent interactions is crucial in chemistry.
- Conformational preferences of organic molecules influence their properties.
- The role of water in modifying molecular interactions is of significant interest.
Purpose of the Study:
- To investigate the structure and hydrogen bonding of the 2-ethylfuran···water complex.
- To determine the conformational preferences of isolated 2-ethylfuran and its hydrated complex.
- To elucidate the influence of water on the energetic ordering of 2-ethylfuran conformers.
Main Methods:
- Chirped-pulse Fourier transform microwave spectroscopy was employed to record rotational spectra.
- Spectra of five isotopologues of the complex were analyzed.
- Quantum chemical calculations were performed to support experimental findings.
Main Results:
- The structure of one conformer of the 2-ethylfuran···water complex was determined.
- The hydrogen bond length was found to be 2.0950(42) Å, with a near-linear angle of 167.69(16)°.
- A weak interaction between water oxygen and the ethyl group was identified, and the energy ordering of 2-ethylfuran conformers was observed to reverse upon hydration.
Conclusions:
- The study provides detailed structural information on the 2-ethylfuran···water complex.
- Hydration by a single water molecule significantly alters the conformational energy landscape of 2-ethylfuran.
- The findings highlight the subtle interplay between hydrogen bonding and van der Waals interactions in molecular complexes.
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